Flexible composite lap joint for trailer flooring

ABSTRACT

A composite wood floor board assembled adjacent to another composite wood floor board, each the board comprising: a top layer of laminated hardwood comprising: a top side; a bottom side; a first lateral side; and a second lateral side opposite the first lateral side, wherein at least one of the first and second lateral sides is formed without shiplap lips; and a bottom layer comprising a planar fiber-reinforced polymer composite that is bonded to the bottom side of the top layer of the laminated hardwood and reinforces the top layer, wherein the bottom layer of fiber-reinforced polymer composite extends laterally outwardly by a distance up to two inches (2″) from the first lateral side of the top layer, and wherein a part of the bottom layer of the composite wood floor board is bonded to the top layer with a first adhesive and a part of the bottom layer is bonded with a second adhesive or sealant.

CROSS-REFERENCED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 14/548,478, filed Nov. 20, 2014, which is a continuationapplication of U.S. patent application Ser. No. 13/012,899, filed Jan.25, 2011, which claims priority to U.S. Provisional Application Ser. No.61/336,914, filed Jan. 28, 2010, all of which are incorporated herein byreference in their entireties.

BACKGROUND 1. Field of the Disclosure

The present disclosure generally relates to a fiber reinforced compositelap joint used in assembling floor boards to produce a load carryingfloor for over the road vehicular trailers and truck bodies, shippingand domestic containers, and rail wagons and flat decks. Moreparticularly, the present disclosure includes a lap joint that is formedby the composite underlayer of at least one composite floor board beingextended at one lateral edge of the board to foul′ a flange or ledge,which is then mated with an adjacent board at a recess to form aflexible lap joint between the boards.

2. Discussion of the Background Art

Composite wood floor boards for trailer flooring are composed of a toplaminated wood layer and a bottom polymer composite layer. The top layeris made of many wood strips having random lengths, which aresignificantly less than the length of the board. The wood strips areedge-glued to make a unitary floor board with an approximate length upto 60 feet and width of 6 to 15 inches. The ends of the wood strips arefitted with a conventional end joint in the form of a hook, butt, fingeror other mechanical or adhesive joint to make a longitudinal connectionwith other strips at the front ends and back ends of the wood strips. Afiber reinforced polymer composite underlayer is at least partly bondedto the bottom side of the wood layer to reinforce the laminated wood andto provide a seal for the wood and end-joints of the wood components inthe boards.

A shiplap is a rectangular projecting lip running along the length at anedge of a floorboard. Typically, the lip extends along the width of aboard by about ⅜ to ½ inch and has approximately half the thickness ofthe board. A “top shiplap” has the lip extending from the top halfthickness of the board. Similarly, a “bottom shiplap” has the lip at thebottom half of the board. The crusher bead is a small semi-circularprojection running along the length on each edge of a board and placedover or below a lip. When the floorboards are assembled side-by-side ina trailer such that the side edges of corresponding boards are squeezedtogether, the top and bottom shiplaps of adjacent boards overlap to forma seam of the shiplap joint. The shiplap joint between adjacent boardshelps to transfer part of the bending and shear load applied on oneboard to its adjacent board. The shiplap joint also helps to prevent theentry of road debris and water or moisture into the trailer. The crusherbead provides spacing between adjacent boards to allow for lateralexpansion of wood layer upon absorption of moisture by the wood. Puttyis applied at the end-joints of wood strips of the boards to fill anyresident gaps. In a typical vehicular trailer, container, truck body orrail wagon, henceforth generically referred to as a trailer, thefloorboards are supported by thin-walled cross-members of I, C or hatsections, each having an upper flange, which span the width of thetrailer and are regularly spaced along the length of the trailer. Eachfloor board is secured to the cross-members by screws extending throughthe thicknesses of the board and the upper flanges of the cross-members.The floor boards with the underlying supports and connections, togetherconstitute the floor system. Ehrlich U.S. Pat. No. 4,703,948, is anexample of prior art trailer floor assembly using shiplap joints offloor boards. The floor system of a van trailer and truck body is loadrated according to Truck Trailer Manufacturers Association, RecommendedPractice (TTMA RP) number 37-02, which is an industry standard in NorthAmerica. In this test, a front axle loaded fork truck makes back andforth passes or load cycles on the floor in a trailer. In order to passthe test at a given load, the floor boards shall not be allowed to crackand fracture in a significant manner. In some cases, where the moisturesealing of the floor system is essential, the floor and the shiplapjoints are required to maintain the initial seal after several thousandload cycles.

Even though the composite underlayer in the form of a flat sheetprotects the wood and end-joints at the bottom side of the wood layer,it does not protect the lateral sides of the boards in a conventionalshiplap joint. Sometimes water from the roadside of the trailer canpenetrate the shiplap joint either through the exposed lateral sides ofend-joints in the wood layer or through any gaps between boards in theshiplap joint. Caulking or sealant is sometimes applied to the shiplapjoint to form a better seal. The composite underlayer can be shaped inthe form of conventional lips of the shiplap as shown in prior art U.S.Pat. No. 5,928,735. This protects the lateral wood sides of the boards,but it requires the forming of the composite shiplaps by the pultrusionprocess using a heated die. This process is relatively slow, costly andcumbersome to practice. In the case of a composite board with a bottomflat layer of composite, there is a need to improve the performance ofthe joint between adjacent boards.

A structural issue with conventional shiplaps is that the strength ofthe shiplap is less than the strength of the floorboard away from theshiplap. This is because the shiplap joint has two overlapping lips,namely the top and bottom lips and the top lip, which is unreinforcedwood is relatively weak compared to the bottom lip with compositereinforcement. The top lip is susceptible to fatigue loads of lift truckload cycles that move cargo on the trailer floor. Further, the lips ofconventional shiplaps are half the thickness of the boards and theytransfer load from one lip to the other lip and thereby cause stressconcentration in the inner corners of the lips. Reduction of stressconcentration in the wood layer and strengthening of the joint ispreferred for higher floor load rating and improved sealing at thejoint.

As shown in FIGS. 1-4, conventional wood floor boards 1, 2 forover-the-road truck trailers and containers is normally manufacturedwith hardwoods such as ash, aspen, elm, yellow-poplar, and preferablyoak, maple, birch, beech and the like, although softwoods such asDouglas fir, larch and spruce can be employed. Tropical wood speciessuch as apitong, kapur, eucalyptus, and keruing are also used. Bamboostrips, which is typically not considered to be wood, but, which is alignocellulosic material like wood can also be used in a generic woodyfloor for trailers. The generic wood floor shall be understood to bemade of lignocellulosic material such as wood or bamboo. A conventionallaminated wood floor board is composed of many wood strips 3, each witha length less than 10 feet. The wood strips are edge-glued to form aunitary board measuring 6 to 15 inches wide and less than 60 feet inlength. The ends of the wood strips are fitted with an end-joint 4 inthe form of a hook, butt, finger or other mechanical or adhesive jointto make a longitudinal connection with other strips at the front end andback end of the wood strips.

In addition, shiplap 5, 6 is typically a rectangular projecting liprunning along the length at an edge of a floorboard. Typically, the lipextends along the width of a board by about ⅜ to ½ inch and hasapproximately half the thickness of the board. A “top shiplap” 6 has thelip extending from the top half thickness of the board. Similarly, a“bottom shiplap” 5 has the lip at the bottom half of the board. Thecrusher bead 7 is a small semi-circular projection running along thelength on each edge of a board and placed over or below a lip. When thefloorboards are assembled side-by-side in a trailer such that the sideedges of corresponding boards are squeezed together, the top and bottomshiplaps of adjacent boards overlap to form a seam 8 of the shiplapjoint. The shiplap joint between adjacent boards helps to transfer partof the applied load from one board to the adjacent board. The shiplapjoint also helps to prevent the entry of road debris and water into thetrailer, but it is not waterproof. The crusher beads provide spacingbetween adjacent boards for lateral expansion of wood upon theabsorption of moisture. A putty is applied at the end-joints of woodstrips of the boards to fill any resident gaps. All the boards aresupported by thin-walled cross-members 9 of I, C or hat sections, eachhaving an upper flange, which span the width of the trailer and arespaced apart along the length of the trailer. The ends of thecross-members are attached to the side rails 10 of the trailer. A floorseal 11 may be used between a side rail and an adjacent floor board.Each floor board is secured to the cross-members by screws 12 extendingthrough the thicknesses of the board and the upper flanges of thecross-members.

In some closed van trailers that are more common in Europe and in someopen flatbed trailers and also in open rail decks, solid wood boards 13are used for flooring. The boards may be finger jointed 14 end-to-end toprovide a long length. In some closed van trailers, a heavy duty steelor aluminum hat-channel 15, also called as omega channel, is usedbetween boards. The channel reinforces the joint between adjacentboards, especially around a finger joint of the boards.

In a composite floor configured for a van trailer (FIG. 1), a compositeunderlayer 16 is bonded to the bottom side of the wood layer 17 of eachboard to reinforce the wood and to provide a seal for the wood andend-joints of the wood components in the laminated boards. The compositeis typically a polymer composite including a polymer matrix such asepoxy, polyester, phenolic, PP or PET and includes one or more ofreinforcing fibers such as glass, aramid, polyethylene, or carbonfibers. The composite layer 16 is adhesively bonded to the bottom sideof the laminated wood layer 17.

A structural problem with conventional shiplaps is that the strength ofthe shiplap is much less than the strength of the floorboard away fromthe shiplap. This is because the shiplap joint has two overlapping lips5, 6 and the top lip 6, which is unreinforced wood is relatively weakcompared to the bottom lip 5 with composite reinforcement. The top lipis susceptible to the fatigue loads of lift trucks that move cargo onthe trailer floor. Since the lips of shiplaps are half the thickness ofthe boards and they transfer load from one lip to the other lip, theload transfer causes stress concentration in the inner corners 18 of thelips upon loading of the flooring with lift trucks. The back and forthmovement of the lift truck on the floor during loading and unloading ofcargo can lead to cracking 19 of the top shiplap (see FIG. 5), which isnot reinforced. Sometimes the bottom lip can crack at the inner corneras well. Composite floors are normally made thinner than conventionallaminated wood floors for similar structural performance in a trailer,however the limitation of the thinner composite floor board is theweakness of the even more thinner shiplaps.

The present disclosure provides a composite lip at one edge of a board,which can be mated with the recess at the bottom side of an adjacentboard. The composite lip is fabricated with the flat sheet compositethat is also used as the underlayer of the prior art composite board.The wood layers of two adjacent boards are not lap jointed as inconventional shiplap joint. This allows for the relative deflection ofone board with respect to the adjacent board without significant loadtransfer and improves flexibility of the joint, which in turn preventscracking of the wood layer at the corners of the lap joint. Further, theelimination of shiplaps, allows for about 4% reduction in the wood usedto make a typical 12 inch wide floor board, thus saving material andcost. The material savings is applicable to all vehicular floors,including closed van and flatbed trailers, truck bodies, containers,rail decks and wagons. By retaining the full thickness of wood at theedges of boards, the strength of the joint is superior to conventionalshiplap joint. The composite lap joint provides a means to eliminate theheavy duty omega channels that are used in some floor systems.Surprisingly, the seal of the composite joint has been found to be leakfree in a smoke test after conducting industry approved dynamic cyclicload test in a van trailer. That is, the use of a composite flangeaccording to the present disclosure allows for the improved sealing ofthe joint and prevents water ingress into the trailer from the roadside,is stronger than a conventional shiplap joint, and saves some of thematerial required to make a floor board compared to conventional floorboard with conventional shiplap design configuration.

SUMMARY OF THE DISCLOSURE

A composite lap joint for the assembly of a first and a second floorboard from a plurality of boards, used to make the floor for a vehiculartrailer, each board composed of a layer of wood at the top side and alayer of fiber reinforced composite at the bottom side, wherein thecomposite layer is at least partly bonded to the wood layer; thecomposite layer of a first board forming a lip, wherein the lip is alateral extension of the composite layer and the lip is disposed underthe bottom side recess of an adjacent second board to form a compositejoint, whereby the joint provides improved flexibility, moisture sealingability at the seam of the joint and higher strength to the edges of theboards.

Preferably, the composite layer of the second board is offset from anedge of the board to provide a recess for disposing the composite lip ofthe first board.

Alternatively, the composite layer of the second board is contouredaround a recess at an edge of the wood layer to provide a space fordisposing the composite lip of the first board.

In one embodiment, the composite lap joint is provided such that asubstantial part of the composite layer away from an edge of a board isbonded to the wood layer with a first adhesive having a lowerflexibility and a part of the composite layer at the edge of the boardnear the lip, is bonded with an adhesive or sealant with higherflexibility and capable of substantial elongation or stretching underload, thus allowing the composite lip to flex and reduce load transferbetween boards.

In another embodiment, a compressible seal, such as a closed celled foamtape or an extruded sealant or an elastomer, is provided between thecomposite lip of a first board and the bottom side of a second board toallow for improved sealing of the joint.

A joint for providing improved structural performance and moisturebarrier between a first and second board in a vehicular trailer floor,the trailer configured in the form of a box or flat deck structure fortransport of goods on the roads or the rails, each of the boards havinga lignocellulosic or wood top layer and a fiber reinforced compositebottom layer adhesively bonded to the underside of the top layer, theboards extending along the length of the trailer and fastened tosupporting sub-structure of the vehicle, the sub-structure consisting ofspaced apart cross-members, the cross-members extending along the widthof the vehicle; the joint formed by laterally extending the compositelayer of the first board at an edge of the board to render a lip belowthe top layer, providing a recess at the bottom side of a second boardalong an edge and disposing the lip of the first board into the recessof the second board.

According to the present disclosure, the composite underlayer of acomposite board is extended by up to about 2 inches at an edge of thefloor board. The extension of the composite layer is mated with thebottom side of an adjacent floor board to form a composite lap joint.The thickness of the top layer at the edges of a board at a compositelap joint is higher than half the thickness of the board. The compositelap joint is therefore stronger than a conventional shiplap joint and italso provides better sealing against water intrusion through the jointfrom the underside of the floor due to the ability of the composite lipto flex under load and not fracture.

In a preferred embodiment, the extension of the composite lip isapproximately ¼ to ¾ inch. In a more preferred embodiment, the extensionof the composite lip is ⅜ inch to ½ inch, both dimensions inclusive.Additionally, crusher beads may be provided at the lateral verticalsides of the top layer of the mating adjacent boards.

Alternatively, the lateral side edge of the wood layer of one board isskewed at an angle relative to the lateral side edge of adjacent boardand the crusher bead is eliminated. The V-shaped grove thus formed atthe lap joint allows for expansion of boards at the top sides uponabsorption of moisture.

In another embodiment, a caulking or sealant is applied to the compositelip before assembly with an adjacent board.

A composite wood floor board assembled adjacent to another compositewood floor board, each the board comprising: a top layer of laminatedhardwood comprising: a top side; a bottom side; a first lateral side;and a second lateral side opposite the first lateral side, wherein atleast one of the first and second lateral sides is formed withoutshiplap lips; and a bottom layer comprising a planar fiber-reinforcedpolymer composite that is bonded to the bottom side of the top layer ofthe laminated hardwood and reinforces the top layer, wherein the bottomlayer of fiber-reinforced polymer composite extends laterally outwardlyby a distance up to two inches (2″) from the first lateral side of thetop layer, and wherein a part of the bottom layer of the composite woodfloor board is bonded to the top layer with a first adhesive and a partof the bottom layer is bonded with a second adhesive or sealant.

The bottom layer of fiber-reinforced polymer composite is laterallyinset up to two inches (2″) from the first lateral side of the toplayer. The composite wood floor board forms part of a floor system for avehicular trailer, container, truck body, rail wagon, or rail deck.

The laminated hardwood further comprises: a hardwood selected from thegroup consisting of oak, maple, birch, beech, and any combinationsthereof, and wherein the planar fiber-reinforced polymer compositecomprises: one or more fibers selected from the group consisting ofglass fiber, carbon fiber, and aramid fiber; and a polymer selected fromthe group consisting of epoxy, polyester, polyurethane, and phenol.

Further objects, features and advantages of the present disclosure willbe understood by reference to the following diagrams and detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the prior art assembly of compositefloorboards with shiplap joint in a trailer.

FIG. 2 is a schematic diagram of the prior art assembly of fingerjointed solid wood or bamboo floorboards using omega channels betweenadjacent boards in a trailer.

FIG. 3 shows the unassembled edges of two adjacent composite floorboards to form a conventional shiplap joint in a trailer floor.

FIG. 4 shows the assembled edges of two adjacent composite floor boardsto form a conventional shiplap joint in a trailer floor

FIG. 5 shows the conventional shiplap joint assembly of two adjacentcomposite floor boards with a cracked lip of a top shiplap.

FIG. 6 shows the unassembled edges of two composite boards to form acomposite lap joint, wherein one edge has a composite lip and the otheredge has an offset composite layer to form a recess at the bottom sideaccording to one embodiment of the present disclosure.

FIG. 7 shows the composite lap joint assembly of FIG. 6 with twoadjacent composite boards with crusher bead on lateral side edges ofboards.

FIG. 8 shows the composite lap joint assembly of two adjacent compositeboards, wherein one edge has a flat composite lip and the other edge hasa bottom recess covered by a contoured composite underlayer according toanother embodiment of the present disclosure.

FIG. 9 shows the composite lap joint assembly of two adjacent compositeboards, wherein the composite lip is partly non-bonded to the bottomedge surface of one board according to yet another embodiment of thepresent disclosure.

FIG. 10 shows the composite lap joint assembly of two adjacent compositeboards, wherein the composite lip is bonded to the bottom edge surfaceof one board with an adhesive or sealant material capable of elasticstretching to increase flexibility of the lap according to still yetanother embodiment of the present disclosure.

FIG. 11 shows the composite lap joint assembly of two adjacent compositeboards, wherein the composite lip is coated with a caulk or seal tape oradhesive before assembly with the edge of an adjacent board according toanother embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Various embodiments of the this disclosure are shown in FIGS. 6-11,attached hereto, wherein FIGS. 6 and 7 show a composite lip 20 at oneedge of a board 22, which can be mated with bottom side edge 21 of anadjacent board 23. Composite lip 20 is fabricated with a planar layer ofcomposite material that is also the underlayer 16 of composite board 22.Top layers 24 and 25 of the two adjacent boards have thicker edges 26compared to the conventional shiplaps, which have half the thickness ofthe board. This makes the edges of boards stronger and resistant tofatigue loading. The composite layer 16 is a fiber reinforced polymer,wherein the polymer is a thermoset or a thermoplastic. Examples ofthermoset polymers can be epoxy, phenolic, polyester, vinyl ester,polyurethane, etc. The fiber reinforcement can be one or more types offibers, such as glass, carbon, graphite, aramid, polyethylene, etc.Additionally, the composite layer 16 may have high strength steel wiresas reinforcement. Preferably, the composite layer is configured toprovide strength and stiffness along the both major axes of the layer.In one embodiment, a portion of the fibers, up to 50% of the totalfibers by weight are oriented approximately along the transverse axis orwidth of the board and the remaining fibers are oriented approximatelyalong the longitudinal axis or length of the board. In anotherembodiment, the composite reinforcement is designed to obtain atransverse tensile strength of the composite layer that is less than itslongitudinal tensile strength. The composite layer 16 may be bonded tothe top layer 24 using any suitable adhesive such as epoxy,polyurethane, hotmelt, acrylic, cyanoacrylate, etc., which may be athermoset or a thermoplastic polymer.

According to the present disclosure, composite underlayer 16 ofcomposite board 22 is extended by up to 2 inches at an edge of the floorboard. The extension of the composite layer is mated with the bottomside of an adjacent second floor board 23 to form a composite lap joint27. The thickness of the wood or lignocellulosic top layer 24 and 25 atthe edges of boards at a composite lap joint is higher than half thethickness of the board. The top layers 24 and 25 may be nearly equal tothe thickness of boards, when the composite layer 16 is relatively verythin. The composite lap joint is therefore stronger than a conventionalshiplap joint and it also provides better sealing against waterintrusion through the joint from the underside of the floor. Thiscomposite lap joint 27 allows for the relative deflection of one boardwith respect to the adjacent board without significant load transferbetween the boards, which in turn prevents cracking of the wood layerthat can happen in conventional shiplap joint. In order to fabricate ashiplap, an additional 7/16 inch wide piece of material is required inthe top layer. In the composite lap joint, the additional material ofthe top layer is saved. The composite layer is offset from one edge tothe other edge of board with no gain or loss of material compared toconventional board with shiplap. This provides a net saving of materialin the top layer to make a board with composite lap compared toconventional shiplap.

In one embodiment, the extension of the composite lip 20 isapproximately ¼ to ¾ inch. In a more preferred embodiment, the extensionof the composite lip 20 is ⅜ inch to ½ inch, both dimensions inclusive.In another embodiment, a crusher bead 7 is included at a lateralvertical edge 26 of the top wood layer of at least one of the twoadjacent boards.

In another embodiment as shown in FIG. 8, composite underlayer 16 offirst board 30 having a crusher bead 7 is extended to form a lip 20 asbefore. Composite underlayer 28 of the second adjacent board 31 iscontoured around a shallow bottom cut profile or rout 29 in the woodlayer at the edge of second board 31, thereby providing a recess belowthe edge of second board 31 for insertion of composite lip 20 of thefirst board 30.

In FIG. 9, composite underlayer 16 adjacent to composite lip 20 of aboard is partly non-bonded to the bottom edge surface 32 of the woodlayer of first board 30. This allows for increased flexibility of thecomposite lip 20 when pushed down by the deflection under load of theadjacent board 31.

In FIG. 10, an adhesive caulk or sealant or an elastomer 33 with highflexibility and elongation or stretch to failure of 100% or more is usedat the bottom edge surface 32 of the first board 30 to allow forincreased flexibility of composite lip 20 and improved sealing of thejoint. Typical caulking and sealant suitable for this application arebased on butyl rubber and polyurethane. Moisture curing polyurethanesealant is commercially available under the trade name Sikaflex fromSika Corporation. The sealant may be applied to the joint at the time ofinstallation of boards in a trailer.

Another embodiment also shown in FIG. 10 depicts lateral side edge 34 ofthe top layer on second adjacent board 31 and side 34 is angled inrelation to the lateral side edge 35 of first board 30 and the crusherbead has been eliminated. The V-shaped grove 36 thus formed at the lapjoint 27 allows for the expansion of wood top layer of boards 30 and 31upon absorption of moisture.

In FIG. 11, a compressible material in the form of a foam tape or asealant 37 is applied on the composite lip 20 for moisture sealing.

A one inch thick composite floor was fabricated for testing theperformance of the composite lap joint of the present disclosure asshown in FIG. 7. The floor was composed of eight boards and there wereseven composite lap joints between adjacent boards. A butyl rubber caulkwas applied on the composite lip during installation of boards in a vantrailer. The floor was supported by 4 inch high cross-members, made ofsteel with minimum yield strength of 80 Ksi, which is a North Americanindustry standard for common van trailers. The cross-members were spacedat 12 inches in the bay section of the trailer. The composite lip 20 was0.5 inch wide and 0.05 inch thick. The composite was made of continuousglass fiber rovings and epoxy resin. About 90% by weight of the glassfiber was approximately oriented in the longitudinal direction of eachboard and the remaining fibers were laid generally across the width ofeach board. The top layer of the boards was laminated oak. Apolyurethane hotmelt adhesive supplied by Forbo Adhesives LLC was usedfor bonding the composite layer to the boards.

The one inch composite floor is desirable for light weight trailers,especially those that are designed for hauling higher density beverageand canned products. It saves over 300 pounds of weight in a typical 53foot dry van trailer compared to the industry standard 1.31 inch thicklaminated oak floor. These trailers require a TTMA floor load rating of16,000 pounds to support the lift truck that moves pallets of beverage.The conventional one inch thick composite floor with shiplap jointbetween boards is not suitable for this type of application due to thestress concentration at the corners of the 0.5 inch thick shiplaps anddue to the high number of load cycles encountered in typical beveragehauling applications.

The cyclical load test of the floor system was conducted according toTTMA RP 37-02. A forklift truck with a front axle load of 16,000 poundswas cycled 3000 times along the center axis of the one inch compositefloor having the composite lap joint in a van trailer. An additional3000 load cycles were applied at the front axle load of 17,500 pounds onthe same floor. After 6000 load cycles on the floor boards, there was noobservable damage to the floor boards on both the top and bottom sidesand at the composite lap joint. After the final completion of thetesting, the loaded floor boards were removed and closely observed forsigns of cracks. The composite lips of the boards were intact withoutany fracture of the transverse glass fibers of the composite layer.Surprisingly, the epoxy resin of the composite was crazed at the cornerof the wood layer and the composite lip. It appeared that the crazing ofepoxy may have increased the flexibility of the composite lip, which inturn helped to avoid gross fracture of the lip and debonding of thecomposite lip from the wood layer. The caulk effectively bonded adjacentboards at the lap joints and maintained a good seal. After thecompletion of the load test, a smoke bomb was placed inside the trailerand the doors were shut to test for leaks. If smoke leaks through thefloor, it is generally considered to be a sign of potential pathways forwater and moisture to migrate to the top side of the floor from the roadside of the trailer. Unexpectedly, the composite lap joints were foundto be free of leaks. This test proved the improved structural andsealing performance of the composite lap joint of the presentdisclosure. This test showed that the floor system was capable ofhandling loads higher than 16,000 lbs and even higher than 17,500 poundsfor thousands of load cycles without compromising the integrity of thecomposite lap joint.

While the composite lap joint has been proven to be particularly usefulfor 1 inch thick floors, it is a better joint for all suitablethicknesses of boards ranging from 0.75 to 1.5 inch. The elimination ofconventional shiplaps saves about 7/16 inch of wood material of the toplayer, which reduces the cost of making a composite floor board at agiven width. The increased strength of the joint allows for theelimination of omega channels that are used in some wood floors, thussaving additional weight and cost, while simplifying the floor design.As such, the composite lap joint is useful in floor systems in a varietyof vehicles, including over the road trailer, truck body, rail decks andwagons. The top layer of the boards can be laminated wood, bamboo, solidwood or other lignocellulosic substrates.

While I have shown and described several embodiments in accordance withmy disclosure, it is to be clearly understood that the same may besusceptible to numerous changes apparent to one skilled in the art.Therefore, I do not wish to be limited to the details shown anddescribed but intend to show all changes and modifications that comewithin the scope of the appended claims.

What is claimed is:
 1. A method of joining a first and second compositefloor boards in a vehicular trailer: wherein the first and secondcomposite floor boards each have a top side and a bottom side, andwherein each of the first and second composite floor boards comprises: alayer of wood at the top side that has opposing lateral side edges,wherein each of the opposing lateral side edges is more than half thethickness of the wood layer and does not form a shiplap, and wherein thewood layers of the first composite floor board and the second compositefloor board are not joined by a conventional shiplap joint; and acomposite layer formed from a layer of non-wood fiber reinforced polymercomposite at the bottom side, and wherein the composite layer is atleast partly bonded to the wood layer with a first adhesive andreinforces the wood layer; a composite lip at one of the opposinglateral side edges of the wood layer of the first composite floor board,the composite lip formed by lateral extension of the composite layer ofthe first composite floor board; and a bottom side recess at one of theopposing lateral side edges of the second composite floor board, formating with the composite lip of the first composite floor board,wherein the method comprises: applying a second adhesive or sealant orcaulk to the composite lip of the first composite board or to the bottomside recess of the second composite floor board or to both of compositelip and recess, disposing the first composite floor board adjacent tothe second composite floor board, and disposing the composite lip underthe bottom side recess of the second composite floor board to form aseam.
 2. The method of claim 1, wherein a part of the composite layer ofthe first composite floor board is bonded to the wood layer of the firstcomposite floor board with a first adhesive, and a part of the compositelayer of the first composite board is bonded to the wood layer of thesecond composite floor board with a second adhesive or sealant.
 3. Themethod of claim 1, wherein at least one of the opposing lateral sideedges of one or both of the first and second composite floor boardsfurther comprises one or more crusher beads.
 4. The method of claim 1,wherein the composite layer of the second composite floor board isoffset from an edge of the layer of wood to provide the bottom siderecess for disposing the composite lip of the first composite floorboard.
 5. The method of claim 1, wherein the composite layer of thesecond composite floor board is contoured around a recess at an edge ofthe wood layer to provide the bottom side recess for disposing thecomposite lip of the first composite floor board.
 6. The method of claim1, wherein the composite layer of first composite floor board ispartially non-bonded to the wood layer at the opposing lateral side edgenear the lip of the first composite floor board.
 7. The method of claim1, wherein the layer of wood comprises a hardwood, and the layer ofcomposite comprises a polymer and reinforcing fibers.
 8. The method ofclaim 1, further comprising applying a compressible seal or caulk or asealant between the first and second composite floor boards.
 9. A methodfor providing moisture barrier between two composite floor boards amonga plurality of composite floor boards in a vehicular trailer: whereinthe composite floor boards having a moisture barrier between themcomprise a first composite floor board and a second composite floorboard, each of the first and second composite floor boards comprising: awood top layer having opposing lateral side edges, wherein each of theopposing lateral side edges is more than half the thickness of the woodlayer and does not form a shiplap; and a non-wood fiber reinforcedpolymer composite bottom layer adhesively bonded with a first adhesiveto an underside of the wood top layer that reinforces the wood layer; acomposite lip at one of the opposing lateral side edges of the woodlayer of the first composite floor board, the composite lip formed bylateral extension of the composite layer of the first composite floorboard; and a bottom side recess at one of the opposing lateral sideedges of the second composite floor board, for mating with the compositelip of the first composite floor board, wherein the method comprises:disposing the first and second composite floor boards along the lengthof a trailer; applying a second adhesive or sealant to the composite lipof the first composite board or to the bottom side recess of the secondcomposite floor board or to both of composite lip and recess, disposingthe first composite floor board adjacent to the second composite floorboard, disposing the composite lip under the bottom side recess of thesecond composite floor board to form a seam, and fastening the floorboards to a supporting sub-structure of the trailer, the supportingsub-structure comprising spaced apart cross-members, the cross-membersextending along the width of the trailer.
 10. The method of claim 9,wherein at least one of the opposing lateral side edges of one or bothof the first and second composite floor boards further comprises one ormore crusher beads.
 11. The method of claim 9, wherein the compositelayer of the second composite floor board is offset from an edge of thelayer of wood to provide the bottom side recess for disposing thecomposite lip of the first composite floor board.
 12. The method ofclaim 9, wherein the composite layer of the second composite floor boardis contoured around a recess at an edge of the wood layer to provide thebottom side recess for disposing the composite lip of the firstcomposite floor board.
 13. The method of claim 9, wherein the compositelayer of first composite floor board is partially non-bonded to the woodlayer at the opposing lateral side edge near the lip of the firstcomposite floor board.
 14. The method of claim 9, wherein the layer ofwood comprises a hardwood, and the layer of composite comprises apolymer and reinforcing fibers.
 15. The method of claim 9, furthercomprising applying a compressible seal or caulk or a sealant betweenthe first and second composite floor boards.
 16. A method of joining theadjacent edges of two composite floor boards in a floor system of avehicle for transporting goods: wherein the composite floor boardscomprise a first composite floor board and a second composite floorboard, each of the first and second composite floor boards having a topside, a bottom side, two opposing lateral sides, and two opposing edges,wherein the top side comprises a layer of wood, and the bottom sidecomprises a layer of fiber-reinforced polymer composite that is bondedto the layer of wood with a first adhesive and reinforces the woodlayer, wherein the fiber-reinforced polymer composite layer comprises afirst portion of fibers oriented along a longitudinal axis and a secondportion of fibers oriented along a transverse axis that strengthen thefiber-reinforced polymer composite layer along both axes, wherein eachof the first and second composite floor boards has a first thickness atone lateral edge and a second thickness at the other lateral edge, andwherein the second thickness is about 75% or more of the firstthickness; and a discontinuity formed between the lateral edge with thefirst thickness of the first composite floor board and the lateral edgewith the second thickness of the second composite floor board, whereinthe method comprises: applying a second adhesive or sealant to thelateral edge with the first thickness of the first composite floor boardand/or the lateral edge with the second thickness of the secondcomposite floor board, disposing the lateral edge with the firstthickness of the first composite floor board adjacent to the lateraledge with the second thickness of the second composite floor board toform a composite lap joint, wherein the composite lap joint is formed bya unitary planar layer of the fiber-reinforced polymer compositebridging the discontinuity between the first and second composite floorboards.
 17. The method of claim 16, wherein the top layer of woodcomprises a hardwood, and the bottom layer of fiber-reinforced polymercomposite comprises fibers selected from the group consisting of glassfibers, carbon fibers, graphite fibers, aramid fibers, polyethylenefibers, and any combinations thereof.
 18. The method of claim 17,wherein the bottom layer is at least partly bonded to the top layer ofthe first or second composite floor board.
 19. The method of claim 18,further comprising a caulk or sealant or a sealing tape applied at thecomposite lap joint between the first and second composite floor boards.20. The method of claim 1 for assembling a floor system of a vehiculartrailer, container, truck body, rail wagon or rail decks.
 21. The methodof claim 9 for assembling a floor system of a vehicular trailer,container, truck body, rail wagon or rail decks.
 22. The method of claim16 for assembling a floor system of a vehicular trailer, container,truck body, rail wagon or rail decks.